Anschaltverfahren und Busanschaltung zum Anschalten einer Baugruppe einer speicherprogrammierbaren Steuerung an einen Bus

摘要

To insert and withdraw subassemblies (2, 3) for a modular, programmable controller during routine operation without disturbance of the data traffic occurring across the bus (5) of the programmable controller, according to the invention an evaluation circuit (13) is arranged in a bus interface (5'). Said evaluation circuit (13) controls a variable resistor (12) which is arranged in one of the supply lines (11', 11") for the subassembly (2, 3) so that said resistor has low resistance when the subassembly is connected to the bus (5), and has high resistance again when a voltage applied at a test inlet (14") of the evaluation circuit (13) is not within a predetermined value range after an acceleration time (T3).